Hi !
1. I have communicated several times with my host who assures me that on their side nothing blocks and everything is up to date.
2. They didn’t give me the version of their curl
3. The error appear in settings > health of site
Yes it’s related by Yoast SEO and it recommend to me to check my SEO with Ryte. I’ve did it. But my website is always index on Google. I verified by myself (site:……)
4. Yes I’ve desactivate all my plugins and remove 2 of thems but not Yoast SEO. The curl error has disappear for the moment. But I’ll check tomorrow one more time.
Now I reloaded the latest PHP version (7.2). Same result, no more Curl. But I prefer to stay standby.